.. currentmodule:: apsw

.. _extensions:

Extensions
**********

SQLite includes a number of extensions providing additional
functionality.  All extensions are disabled by default and you need to
:ref:`take steps <setup_build_flags>` to have them available at compilation
time, to enable them and then to use them.

.. _ext-fts3:

FTS3/4/5
========

FTS3 is the third version of the `full text search
<https://sqlite.org/fts3.html>`__ extension.  It
makes it easy to find words in multi-word text fields.  You must
enable the extension via :ref:`setup.py build flags
<setup_build_flags>` before it will work.  There are no additional
APIs and the `documented SQL
<https://sqlite.org/fts3.html>`__ works as is.

Note that FTS4 is some augmentations to FTS3 and are enabled whenever
FTS3 is enabled as described in the `documentation
<https://sqlite.org/fts3.html#fts4>`__

`FTS5 <https://www.sqlite.org/fts5.html>`__ addresses some issues in the earlier
FTS versions by `breaking backwards <https://www.sqlite.org/fts5.html#appendix_a>`__
compatibility.

.. _ext-icu:

ICU
===

The ICU extension provides an `International Components for Unicode
<http://en.wikipedia.org/wiki/International_Components_for_Unicode>`__
interface, in particular enabling you do sorting and regular
expressions in a locale aware way.  The `documentation
<https://sqlite.org/src/finfo?name=ext/icu/README.txt>`__
shows how to use it.

.. _ext-json1:

JSON1
=====

`Provides functions <https://www.sqlite.org/json1.html>`__ for managing `JSON
<https://en.wikipedia.org/wiki/JSON>`__ data stored in SQLite.

.. _ext-rbu:

RBU
===

Provides `resumable bulk update <https://www.sqlite.org/rbu.html>`__ intended for
use with large SQLite databases on low power devices at the edge of a network.

.. _ext-rtree:

RTree
=====

The RTree extension provides a `spatial table
<http://en.wikipedia.org/wiki/R-tree>`_ - see the `documentation
<https://sqlite.org/rtree.html>`__.
You must enable the extension via :ref:`setup.py build flags
<setup_build_flags>` before it will work.  There are no additional
APIs and the `documented SQL
<https://sqlite.org/rtree.html>`__
works as is.